The present invention relates to a composite ferrule having high performance attributes for use in a connector for connecting optical fibers.
As shown in FIG. 1A, a ferrule for use in a connector for connecting optical fibers generally has a structure wherein one end of a ferrule base section 1 formed with an optical fiber wire insertion bore 1B is coupled to a flange section 3 formed with an optical fiber core wire guide portion 2B.
Further, for the purpose of cost reduction, the ferrule base section 1 is divided into two segments, namely a leading terminal portion made of hard material such as zirconia ceramic, and a remaining trailing terminal portion made of material such as synthetic resin with a lower hardness than the zirconia ceramic (as disclosed in (1) Japanese Patent Application Laid-Open No. 2000-28856, (2) Japanese Patent Application Laid-Open No. 2000-98179, (3) Japanese Patent Application Laid-Open No. 2001-215358 and (4) Japanese Patent Application Laid-Open No. 2001-208936.
To be more precise, a composite ferrule disclosed in the publication (1) is comprised of a sleeve formed with an insertion bore to allow an optical fiber to be inserted, and a resin molded product over-molded to the sleeve. Then, a composite ferrule disclosed in the publication (2) is comprised of a ferrule made of raw materials such as ceramic particles or metallic particles by injection molding, and a cylindrical body, which is coupled to the ferrule, with a flange made of metal. Further, a composite ferrule disclosed in the publication (3) is comprised of a cylindrical capillary formed with an aperture to insert an optical fiber wire, and a cylindrical flange made of resin, which is formed in an outer circumferential periphery of the cylindrical capillary, Furthermore, as shown in FIG. 1B, a composite ferrule disclosed in the publication (4) is comprised of a leading terminal member 1A made from ceramic, and a trailing terminal member 2A made of plastic so as to be unitarily formed with a rear end portion of the leading terminal member.
With these ferrules, for the purpose of cost reduction, only the leading terminal member 1A is formed of hard material such as zirconia ceramic, whereas the remaining trailing terminal member 2A is formed of material, such as stainless or synthetic resin, with a lower hardness than that of the leading terminal member 1A.